Romans 8:5-7 says, "5 For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit. 6 For the mind set on the flesh is death, but the mind set on the Spirit is life and peace, 7 because the mind set on the flesh is hostile toward God; for it does not subject itself to the law of God, for it is not even able to do so..."
People studying cognitive psychology have discovered that every thought you and I have pushes us a little closer to either despair or happiness. So the challenge is to be careful which thoughts you entertain, and which ones you refuse to allow in your head for more than a moment. For scientists, this is a relatively new discovery.
But Paul, the author of Romans, evidently grasped this idea a long time ago. He says that every thought we have takes us a little closer not to happiness or despair, but to either life or death. The mind set on the spirit is life, while the mind set on the flesh is death.
Every thought takes us closer to one or the other, and we get to choose. You can often tell which destination people have chosen long before they ever arrive. If they are cold, aloof, judgmental, haughty, lacking in compassion grace and forgiveness, and this is their regular demeanor, then you can tell the end they have chosen for themselves. If on the other hand they are joyful and welcoming and gracious and forgiving and compassionate and open-handed, you can tell that they have chosen a different destination for themselves.
It is interesting and quite sad that both of these groups of people can sit in the same room on Sundays, sing the same songs, pray the same prayers, nod at the same place to the same sermon, and yet the thoughts and resulting attitudes and actions of one leads to life, while those of the other seemingly lead to death.